This invention relates to a cleaning system for precluding the formation of obstructions about the drain of boilers or the like.
Various devices have been employed to clean the surfaces of furnaces, boilers and other heat exchange devices. Soot-blowing systems of the so-called "puff type" are utilized. These devices discharge steam in a succession of relatively short blasts against the surfaces to be cleaned. These devices present a "lance"/shaft having a nozzle at one end which is inserted into the boiler. The nozzle injects a cleansing fluid, such as steam, which is directed onto the surface, e.g. boiler walls, in an attempt to blow away accumulated soot and ash. Due to the high internal operating temperature of the boiler, the nozzle end of the lances are inserted into the boiler for a short period of time only so as to protect their operating mechanisms. Hundreds of such lances are required for use with huge power plant boilers.
In certain boilers such as those used in coal fired power plants, ash elimination is accomplished either by a carryover (dry particulate) method or by a bottom drain method depending on the state of the by-products of burning. In the latter method it is essential that the ash remain molten, i.e. slag. Otherwise, it will adhere to all metal surfaces. However, this molten slag tends to solidify at the furnace floor drain above the slag tank. This solidification will cause the subsequent slag deposits to flow over the previously solidified slag. If the slag deposits are not removed the deposits will eventually form layers and obstruct the furnace drain commonly referred to as the "monkey" hole. The formation of such obstructions results in a decrease in operating efficiency. In some cases it is necessary to shut the furnace down and remove the solidified slag deposits by air hammers and/or dynamite.
The above-described prior art soot blowers are not sufficient to preclude such obstructions of the "monkey" hole. Such prior art soot blowers rely on steam as a cleaning agent and are designed to operate in a "puff" like manner, i.e. a continuous flow of steam at a constant pressure is directed at the surface to be cleaned. Such fluid flow is designed to remove dry particulate ash from the interior boiler surfaces. However, these blowers are not designed for removal of the heavy molten slag forming at the "monkey" hole of the boiler.
In response thereto a cleansing system is presented which utilizes a blast of compressed high pressure air for removal of the accumulated molten slag. Compressed air is routed to an accumulator at high pressure for increasing the air volume. Extending from this accumulator is an air conduit having an open nozzle at the distal end thereof. The distal end terminates at the monkey hole from the underside of the surrounding drain floor. A control unit allows the large volume of pressurized air residing in the accumulator to be selectably or periodically directed at the monkey hole. This blast of air impacts the molten slag passing through the hole and/or accumulating therearound. The instantaneous impact of the large volume of relatively cold, high pressurized air chills and vibrates the molten slag. This action forms a plurality of particulate materials which fall into the slag tank therebelow. Various nozzle designs employing a primary blast of air through the monkey hole and optional, smaller concurrent air blasts for direction about the monkey hole can be utilized. The system precludes the formation of slag deposits in the monkey hole and subsequent obstruction thereof. Such system is adaptable for use in precluding the formation of deposits on other structures.
It is therefore an important object of this invention to provide a device for elimination of molten slag/pluggage from boiler and/or furnace component surfaces, e.g. the drain/"monkey" hole of a furnace or the like.
Another object of this invention is to provide a device, as aforesaid, which impacts and chills the molten slag in a manner to change the same into smaller particulates for subsequent removal.
Another important object of the invention is to provide a device, as aforesaid, which utilizes an instantaneous blast of a large volume of high pressurized air as the cleaning agent.
A further object of this invention is to provide a device, as aforesaid, which uses blasting acoustics to preclude slag formation about the monkey hole.
Another object of this invention is to provide a device, as aforesaid, which is suitable for use below the drain floor of the furnace proper.
A more particular object of this invention is to provide a device, as aforesaid, which either directs the entire volume of high pressure air through the monkey hole center and/or disperses the air in a succession of smaller blasts therearound.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.